Hepatic encephalopathy (HE) is a complication that presents in as many as 28% of patients with cirrhosis, and reported up to ten years after the diagnosis of cirrhosis. Commonly, it is observed in patients with severe hepatic failure and is characterized by neuropsychiatric manifestations that can range in severity from a mild alteration in mental state to a coma; additionally, some neuromuscular symptoms can be observed. This complication of either acute or chronic hepatic disease is the result of a diminished hepatic reservoir and inability to detoxify some toxins that originate in the bowel. Today, the role of astrocytes, specifically the Alzheimer type II cells, is known to be very important in the pathogenesis of the hepatic encephalopathy, and will be reviewed later. In conclusion, the objectives of this review are: To understand the pathogenesis of hepatic encephalopathy, To recognize the precipitating factors, as well as preventive measures for the development of the hepatic encephalopathy, To describe the new classification of hepatic encephalopathy and its clinical implications, To recognize the clinical manifestations and stages of the disease, To understand the main diagnostic tests used to detect the hepatic encephalopathy, To describe the main therapeutic treatments of hepatic encephalopathy.